A semiconductor device may include several different materials in order to benefit from differences in their properties, for example in physical parameters like electrical and/or thermal conductivity. By way of example, a semiconductor may be combined with a metal structure in order to exploit their difference in electrical conductivity, e.g. a (relatively thick) conductive metal layer, for example a copper layer, may be arranged on a semiconductive silicon wafer. The parameter that may mainly be exploited in the material combined with the semiconductor may be referred to as a primary parameter.
However, the differences in properties may incur problems during manufacture and/or use of the semiconductor device. For example, the different materials, e.g. the copper and the silicon, may differ in their coefficients of thermal expansion (CTE). A temperature change of the semiconductor device may thus lead to mechanical tension in the device, and eventually a defect may occur in the device, for example due to a break in one of the materials or in the connection between the two materials.
The metal layer may be formed in a way that makes it more flexible, such that it can follow the thermal expansion of the silicon, for example by making the layer thin and/or porous (e.g. using plasma deposition or porous printing). However, the electrical (and thermal) conductivity and the heat capacity of such layers is usually much lower than that of solid thick metal layers.
As an alternative that aims at preserving desired properties (e.g. high electrical and/or thermal conductivity) as much as possible, while bridging the undesired differences in properties (e.g. having a coefficient of thermal expansion between those of the metal and the semiconductor), a composite material may be provided, for example instead of the solid, thick metal layer.
Typically, composite materials, for example a composite material comprising copper and carbon, may be formed by means of sintering, for example using high pressure and high temperature. However, it may not be possible to perform a sintering process on a carrier such as a silicon wafer, for example a processed and/or structured silicon wafer, without damaging the carrier through the high pressures and temperatures involved.